6. As illustrating the additions to expenses because of increased track maintenance on account of fast passenger and mail trains, we have made a study of statistics, using the Interstate Commerce report of 1906 as a basis, of seven roads having a large proportion of fast passenger service and seven roads having a moderate speed passenger service, but with a large proportion of freight service. On the roads first named the average cost of maintenance of way per mile was $2,951, and on roads in the latter class $1,565. The operating expenses per train mile in the former class were $1.47, and in the latter $1.33. The roads in the former class, on account of large number of excessively high-speed trains, were obliged to double-track their lines, which directly increased maintenance expenses. PAY FOR RAILWAY POSTAL CARS. The large reduction made by Act of March 2, 1907, in pay for railway postal cars was made in face of large increase in the cost of constructing such cars, due to higher prices of labor and material and greater cost of meeting the more exacting specifications of the Postoffice Department. Changing to steel construction, increases in weight, and generally heavier operating expenses, have created an extremely large increase in cost of moving these cars. The standard railway postal car of only a few years ago, 60 feet long, weighed 80,000 pounds and cost about $5,500. The standard railway postoffice cars, 60 feet long, of wooden construction, used on the railroads with which I am connected, weigh over 100,000 pounds each, or one-fourth more weight, and costs 40 per cent. more, whilst our new standard postal cars of steel construction weigh 108,000 pounds and cost over $9,000, or 60 per cent. more than the car of a few years ago. An argument sometimes made in favor of a lowering of R. P. O. car pay is that for apartment cars used in runs where mail density does not require a full car, no additional compensation is allowed. But we feel that a fair consideration of the circumstances under which mail is handled as compared with other traffic will justify the conclusion that this is not an argument in favor of reducing R. P. O. pay, but rather for allowing the railroad additional compensation for the apartment cars as well. Both services require the furnishing of special features in the way of traveling postoffices not required except for the convenience of the Postoffice Department to enable it to do work while mail is in transit, such as ordinarily performed in office buildings. The full postal car is more expensive to the roads, as it always means additional car service, whilst in some cases of apartment cars the space not occupied by the traveling postoffice is adequate to take care of baggage and express, though very frequently this service also means additional car movement that would not be necessary but for the postoffice feature.